1. Field of the Invention
The invention is a new internal combustion engine that reduces the formation of NOx and increases fuel energy utilization efficiency. The primary field of application is motor vehicle engines.
2. The Prior Art
The growing utilization of automobiles greatly adds to the atmospheric presence of various pollutants including oxides of nitrogen and greenhouse gases such as carbon dioxide. Internal combustion engines used in passenger vehicles average about 15% thermal efficiency in urban driving and have peak efficiencies of about 35%. Even when considering peak efficiency, current engine designs discard almost two thirds of the heat energy supplied to them through the engine coolant system or through the exhaust gas.
The chemical energy contained in fuel is converted into heat energy when it is burned in an engine. Since this combustion takes place in a closed volume (the combustion chamber of the engine), the increased temperature of the combustion gases (and in some cases the increased number of moles of the combustion gases as compared to the reactants) results in an increase in pressure of the system. As the volume of the combustion chamber expands, e.g., the piston moves, work is performed. The increased temperature resulting from combustion, which occurs before the piston begins its rapid expansion, results in the oxidation of some atmospheric nitrogen to form NOx.
Characteristics of conventional engines result in much of the available heat energy being wasted via three routes. First, the combustion chamber is cooled by liquid or air, thus reducing pressure and the potential for work. Second, the expansion process does not fully expand to fully utilize the pressure of the combustion chamber, as the expansion ratio is usually limited by the compression ratio. Third, much heat remains in the exhaust gas.